Collector contact for electrical distribution system



Sept. 17, 1935. H. J. 1.. FRANK 2,014,929

COLLECTOR CONTACT FOR ELECTRICAL DISTRIBUTION SYSTEM Filed April 4, 1855 l I '1 UL-- :1: I II .J L \1.

INVENTOR.

ATTORNEY.

Patented Sept. 17, 1935 PATENT orrice A i 2,014,929, COLLECTOR CONTACT FOR ELECTRICAL DISTRIBUTION. SYSTEM Harrison J. L. Frank lletroit, Mich. I Application April 4, 1935, Serial No. races I 4 Claims.

This application relates to the art of electrical distribution systems and more particularly to that class of suchsystems comprising runs of duct in which ride trolley type collectors.

Systems of this character generally comprise a duct run having closely adjacent copper bus bars therein upon which roll the roller contacts of trolley type collectors, the contact pressure of the roller contacts on the bus bars in most cases being of substantial amount because these Q0115- tacts are often spring pressed. Trolley collectors of this character are generally reciprocated in the duct, and it has been found in the use of systems or this character that in installations where I 1 the reciprocation o1 trolley collector contacts under contact pressure is extremely rapid and frequent, that electrical disturbances in the nature of short circuits very often occur, with consequent damage to the duct and to the trolley collectors. q e V .Anintensive studyof the problem of preventing such shortcircuits'revealed the following hitherto uiiknown facts; It was first discovered that the rapid 'and frequent reciprocation of such trolley collectors in ducts, with the consequent rapid and frequent oscillatory rolling of the roller contacts under considerable contact, pressure on the copper bus bars caused crystallization of the encaged surfaces of these bus bars, similar to that which occurs when copperis rolled through hardening rollers.

. f p 1 It was further discovered that such crystallization caused the engaged surfaces 01 the bus bars to fiake'oif; that the flags gathered in the ducts and provided creepage paths between the bus bars of opposite polarities; and that the presence of short 50 or a film of oil between the roller contacts and the bus bars. This means comprises roller contacts composed of a material o1. such a nature as to be electrically conducting, mechanically satisfactory for withstanding the wear that occurs 55 due to rapid and ireq'uent rolling under pressure on copper bus bars, and yet that was porous so that it could be saturated with a supply of oil and could be considered as carrying its own oil supply. Investigation revealed the existence iof such a material and the same was substituted for 5 the steel or copper commonly used in roller 7 contacts.

The present invention comprises therefore,

means for preventing electrical disturbances such as short circuits or the like in electrical distribu 10 tion systems of the trolley and duct type created by the crystallization of engaged bus bar surfaces due to rapid and frequent reciprocation oi! roller contacts on these bus bar surfaces, which means maintains a film of electrically conducting 15 oil between the roller contacts and the engaged surfaces of the bus bars; the means is embodied in a contact roll of an electricalLv conducting material porous enough to" retain in saturation a quantity of electrically; conducting oil sufllclentto maintain a him of oil between the roller contact and the engagedsuriace of a bus bar, and thus eliminate crystallization of the busbar as the contact rolls along the'same.

For an understanding of the invention reference should be had to the specification and draw-- ing forming part of this application. In the The figure shows an electrical distribution sys--' tem of the duct and trolley collector type wherein the trolley collector roller contacts are of an elec trically conducting material of suficlent porosity to retain in saturation a quantity of oil.

A system of the character under consideration generally comprises a duct run it having insulatedly mounted therein copper bus bars i I, upon which roll the roller contacts E2 of trolley type collectors M, having stirrups 2d mounting the contacts. The roller contacts i2 are generally spring-pressed towards the bus bars so that adequate contact pressure is maintained between the roller contacts and the bus bars.

The roller contacts are of electrically conductlng material of sufficient porosity to retain in saturation a suitable quantity of oil. One such material is marketed under the trade name Oilite, and this material, as known at present, may aptly be termed porous copper, retaining in saturation a considerable quantity or oil.

I claim: W

1. For use with electrical distribution systems of the duct and trolley collector type wherein copper roller contacts reciprocate rapidly and irequently and under adequate contact pressure upon engaged surfaces oi copper bus bars dis- 7 posed in closely adjacent relation, roller contacts whose contact rolls are of copper of suil'icient porosity to maintain in saturation a quantity of oil suillcient to provide a film of electrically conducting lubricating oil between the contact roll engaging surfaces and the surfaces of the bus bars engaged thereby of sumcient thinness to avoid disturbance of electrical contact between 0! the duct and trolley collector type wherein metal roller contacts of good electrical conductivity reciprocate rapidly and frequently and under adequate contact pressure upon engaged surfaces of metal bus bars 01 good electrical conductivity disposed in closely adjacent relation,

roller contacts whose contact rolls are or electrically conducting metal of suiiicient porosity to maintain in saturation a quantity of oilsutilcient to provide a film 0! electrically conducting lubricating oil between the contact roll engaging surfaces and the sm'taces of the bus bars engaged thereby of suiliclent thinness to avoid disturbance or electrical contact between the contacts and the bus bars.

3. A construction of the character described in 10 claim 2 wherein copper is a principal constituent of the metal used for the rollers.

4. A construction of the character described in claim 2 wherein copper is a principal constituent of the metal used for the rollers and the bus bars. 15

HARRISON J. L. FRANK. 

